Abstract: An arrangement for forming a block in a cable against transmission of fluid along the cable comprises a generally flat blocking array (1) that is formed from a fusible polymeric sealant, e.g. a hot-melt adhesive or a thermosetting adhesive, which has a number of passage ways (2) extending from one end of the array to the other end for receiving wires (4) of the cable. The assembly includes a heat-shrinkable covering that can be positioned around the blocking array (1) in its flat configuration and recovered about the array by application of heat, and the sealant is capable of melting during recovery of the covering and being forced from a generally flat configuration to a generally cylindrical one by recovery of the covering. The invention also includes arrays per se which may be formed from hot-melt adhesives or thermosetting adhesives.